i recommend sygate they offer a free version and im very happy with the pro version also uses the least amount of memory i have with good power and feedback, it also alerts u anytime a program has changed, aka updated itself, sygate asks u do u want to let it assess internet bec it is a different file from the past and that is a great feature many softwares lack. i have not used kerio yet, but so far ive heard good things about it according to this forum, i have used NIS (norton internet security) made by symantec in the past and was happy with that but too much configuring as sygate makes it much easier and i believe that the pro edition is stronger and almost easier to config.... goodluck ask me more if u want ive tried a bunch of things